WASHINGTON — Alfalfa sprouts recalled because of salmonella poisoning were sold to more than 400 Wal-Mart stores in 15 states, a spokeswoman for the retail chain said today.

The raw sprouts sold by Caldwell Fresh Foods were sold to Wal-Marts in Alabama, California, Georgia, Iowa, Illinois, Indiana, Kansas, Kentucky, Louisiana, Missouri, Mississippi, Nebraska, Nevada, Oregon and Wisconsin, the company said.

The federal Centers for Disease Control said last week the alfalfa sprouts appear to have sickened at least 22 people in 10 states, including a baby in Oregon. Eleven of those sickened were in California.

The sprouts were sold in at least seven other stores in California, including Trader Joe’s. Caldwell, based in Maywood, Calif., said in a release that the sprouts were sold at restaurants, delicatessens and retailers nationwide. But the company has not released a complete list of the outlets that purchased the sprouts.

Caldwell Fresh Foods did not respond to requests for comment and no one answered the phone at the company’s headquarters today.

According to the Oregon Department of Human Services, which was first to announce the outbreak last week, Caldwell’s alfalfa product was sold in 18 states in the West, Midwest and South.

In addition to those who were sickened in California, two were sickened in Nevada and two in Wisconsin. Arizona, Oregon, Idaho, Illinois, Missouri, New Mexico and Colorado each had one person become ill, the CDC said. The illnesses began between March 1 and May 2 and six people were hospitalized.

Salmonella is an organism that can cause serious and sometimes fatal infections in those with weakened immune systems. It can cause diarrhea, fever and vomiting.

Wal-Mart spokeswoman Caren Epstein said sprouts were removed from the produce departments of the affected stores as soon as the retail chain was made aware of the recall. She said 75 Wal-Marts in Illinois, 56 Wal-Marts in Georgia and 47 Wal-Marts in Louisiana purchased the sprouts. The rest of the stores were spread through the remaining 12 states.

Caldwell said the recalled alfalfa sprouts were sold in plastic cups and plastic bags under the Caldwell Fresh Foods brand, plastic cups under the Nature’s Choice brand and plastic containers under the California Fresh Exotics brand.

William E. Keene, a senior epidemiologist at the Oregon health department, said the baby sickened was a 4-month-old boy who ate alfalfa sprouts mixed with other foods. His sickness made the cause of the outbreak easier to identify, Keene said, because the infant had not yet eaten many foods. He was hospitalized but later recovered.

Alfalfa sprouts are grown in a warm, humid environment, heightening the chances of salmonella, listeria or E. coli infection. According to Foodsafety.gov, a website run by several government agencies that oversee food safety, there have been at least 30 reported outbreaks of foodborne illness associated with different types of raw and lightly cooked sprouts since 1996.

The government has long recommended that children, the elderly, pregnant women, and people with weakened immune systems should avoid eating raw sprouts of any kind — that includes alfalfa, clover, radish, and mung bean sprouts. The government website recommends consumers cook sprouts to kill the bacteria and request that sprouts not be added to their food at restaurants.

This is the second large multistate outbreak in fresh produce announced this month. Twenty-six people were sickened by an outbreak of E. coli in romaine lettuce in Michigan, New York, Ohio, Tennessee and Pennsylvania. Seven additional cases are suspected, the CDC said.